Internal combustion engines typically include an air intake system, a combustion chamber, and an exhaust system. The air intake system drives air into the engine combustion chamber. The air intake system is pressurized, for example, by a turbocharger, to drive the air into the combustion chamber during an intake cycle. Air and fuel are combined in the combustion chamber. Exhaust gas is emitted from the combustion chamber during an exhaust cycle.
Internal combustion engines are known to include exhaust gas recirculation (EGR) systems to reduce nitrous oxide (NOx) emissions. A fraction of the exhaust gas is diverted from entering the turbine and routed back through an EGR system into the intake manifold. The resultant air charge to the cylinder contains both fresh air and combusted exhaust gas. It is desirable to improve EGR flow rate to reduce engine emissions while maintaining reasonable fuel economy performance. If a sufficient volume of exhaust gas is not recirculated, the desired impact may not be achieved.
Accordingly, there is a need for an EGR system that provides a volume of recirculated exhaust gas to achieve the desired EGR impact.